scholarly journals Vortical flow. Part 1. Flow through a constant-diameter pipe

2002 ◽  
Vol 463 ◽  
pp. 259-291 ◽  
Author(s):  
T. W. MATTNER ◽  
P. N. JOUBERT ◽  
M. S. CHONG
Keyword(s):  
Axial Velocity ◽  
Test Section ◽  
Velocity Profiles ◽  
Vortical Flow ◽  
Outer Flow ◽  
Spiral Vortex ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Through ◽  
Streamwise Distance

This paper describes an exploration of the behaviour and properties of swirling flow through a constant-diameter pipe. The experiments reveal a complicated transition process as the swirl intensity Ω is increased at fixed pipe Reynolds number Re ≈ 4900. For Ω [les ] 1.09, the vortex was steady, laminar, axisymmetric, and developed slowly with streamwise distance. The upstream velocity profiles were similar to those commonly appearing in the literature in similar apparatus. Spiral vortex breakdown appeared in the test section for 1.09 [les ] Ω [les ] 1.31 and was associated with a localized transition from jet-like to wake-like mean axial velocity profiles. Further increase in Ω caused the breakdown to move upstream of the test section. Downstream, the core of the post-breakdown flow was unsteady and recovered toward jet-like profiles with streamwise distance. At Ω = 2.68, a global transition occurred in which the mean axial velocity profiles suddenly developed an annular axial velocity deficit. At the same time, disturbances began to appear in the outer flow. Further increase in Ω eventually led to an annulus of reversed axial flow and a completely unsteady vortex.

scholarly journals Transient Behavior of Vortical Flow through a Constant Diameter Pipe

2001 ◽  
Vol 13 (9) ◽  
pp. S8-S8 ◽  
Author(s):  
T. W. Mattner ◽  
M. S. Chong ◽  
P. N. Joubert
Keyword(s):  
Transient Behavior ◽  
Vortical Flow ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Through

scholarly journals Vortical flow. Part 2. Flow past a sphere in a constant-diameter pipe

2003 ◽  
Vol 481 ◽  
pp. 1-36 ◽  
Author(s):  
T. W. MATTNER ◽  
P. N. JOUBERT ◽  
M. S. CHONG
Keyword(s):  
Vortical Flow ◽  
Flow Past ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Part ◽  
Flow Past A Sphere

Decaying, Swirling Flow in a Pipe: Axial Velocity Field Development With Reversed Axial Flow

2003 ◽  
Author(s):  
Heather L. McClusky ◽  
Donald E. Beasley
Keyword(s):  
Velocity Field ◽  
Axial Velocity ◽  
Vortex Breakdown ◽  
Swirling Flow ◽  
Axial Flow ◽  
Axial Direction ◽  
Velocity Profiles ◽  
Field Development ◽  
Constant Diameter ◽  
Spatial Oscillations

Streamwise development of the axial velocity field in a confined, decaying swirling flow is explored in the present study. A tangential injection mechanism produces swirling flow at the inlet of a constant diameter pipe. Particle image velocimetry is employed for axial velocity measurements. Representative axial velocity profiles are presented for axial locations of 3 to 67 pipe diameters. The axial velocity profiles are asymmetric relative to the pipe centerline and the asymmetries persist as the flow develops in the axial direction. The eccentricity of the swirling flow spatially oscillates as the flow develops in the axial direction. The spatial oscillations of the axial velocity suggest that a vortex breakdown may be located near the inlet of the pipe and the entire pipe is the wake region of the vortex breakdown. The centerline axial velocity is also used to document the axial development of the flow. A comprehensive view of the flow field is provided by considering theoretical explanations presented in the literature for decaying, swirling pipe flows and for vortex breakdown.

Velocity Profiles of Liquid Flow Through Circular Tubes and How They Affect Flow Measurement

1991 ◽  
Vol 113 (3) ◽  
pp. 206-210 ◽  
Author(s):  
D. Yogi Goswami
Keyword(s):  
Transition Region ◽  
Laser Doppler Velocimetry ◽  
Flow Measurement ◽  
Velocity Profiles ◽  
Turbulent Regime ◽  
Flow Meters ◽  
Circular Tubes ◽  
Flow Through ◽  
Hydrogen Bubble Technique

This paper analyzes velocity profiles for flow through circular tubes in laminar, turbulent, and transition region flows and how they affect measurement by flow-meters. Experimental measurements of velocity profiles across the cross-section of straight circular tubes were made using laser doppler velocimetry. In addition, flow visualization was done using the hydrogen bubble technique. Velocity profiles in the laminar and the turbulent flow are quite predictable which allow the determination of meter factors for accurate flow measurement. However, the profiles can not be predicted at all in the transition region. Therefore, for the accuracy of the flowmeter, it must be ensured that the flow is completely in the laminar regime or completely in the turbulent regime. In the laminar flow a bend, even at a large distance, affects the meter factor. The paper also discusses some strategies to restructure the flow to avoid the transition region.

Modeling of the Ionized Fluid Flow through a Cone-Shaped Nanopore

2007 ◽  
Vol 121-123 ◽  
pp. 1089-1092 ◽  
Author(s):  
Jian Zhong Fu ◽  
Xiao Bing Mi ◽  
Yong He ◽  
Zi Chen Chen
Keyword(s):  
Fluid Flow ◽  
Theoretical Analysis ◽  
Cross Section ◽  
Debye Length ◽  
Velocity Profiles ◽  
Gradual Change ◽  
Ion Flow ◽  
Flow Through

Theoretical analysis of the ionized fluid flowing through a cone-shaped nanopore is presented. The internal cross section of the cone-shaped channel is in the range from micro- to nanometer and gradual change from larger to smaller than the Debye length for the ions. The model is developed to predict the ionized fluid flow behaviors in cone-shaped micro/nanochannels. The velocity profiles of ion flow that occur in nanopores are obtained.

A Combined CFD/MRV Study of Flow Through a Pin Bank

2014 ◽  
Author(s):  
Mike Siekman ◽  
David Helmer ◽  
Wontae Hwang ◽  
Gregory Laskowski ◽  
Ek Tsoon Tan ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Velocity Field ◽  
Turbulence Model ◽  
Field Data ◽  
Peak Velocity ◽  
Velocity Profiles ◽  
Mean Velocity ◽  
Magnetic Resonance Velocimetry ◽  
Sst Turbulence Model ◽  
Flow Through

RANS and time averaged URANS simulations of a pin bank are compared quantitatively and qualitatively to full 3D mean velocity field data obtained using magnetic resonance velocimetry (MRV). The ability of the CFD to match MRV velocity profiles through the pin bank is evaluated using the SST turbulence model. Quantitative comparisons of the velocity profiles showed an overprediction of peak velocity by the CFD at the first pin rows, and a smaller oscillatory error that diminishes as it moves through the pins, resulting in better matching towards the exit.

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